Water Quality and Temperature are Important
The quality of the water used by any abrasive waterjet plays a very important role in the life of certain critical components, such as the nozzle orifice, on/off valves, seals, check valves and plungers. Most affected is the high-pressure nozzle orifice. To perform high quality cutting, the orifice needs to create a high quality jet that is directed through the center of the mixing tube. Contaminates in the water can create a multitude of problems for the orifice.
These contaminates can be classified into two groups: dissolved solids and suspended solids. Particles suspended in the water impact the edge of the orifice and can chip it. This results in poor jet quality, poor cutting capability and lowered mixing tube life. Solids that are dissolved can collect onto the entrance of the orifice. Over time, a ring of precipitate builds up around the orifice. Eventually, a portion of this ring breaks and damages the orifice or disrupts jet quality.
Water that is too pure also causes problems with high-pressure components. Since the water is so pure, a high potential exists for the water to dissolve materials that it comes in contact with. Excessive water treatment can be detrimental to components in the high-pressure water system.
There must be a balance between pure water and untreated supply water. Ultimately, the cost of water treatment must be compared to the costs resulting from shortened component life and cutting equipment downtime. The local water supply should always be tested prior to the installation of any waterjet cutting system. This permits an appropriate water treatment system to be selected and installed. Required water treatment may range from nothing at all to simple filters, water softeners or a reverse osmosis system.
A byproduct of increased pressure is heat. Since the water used in the OMAX® JetMachining® system is pressurized to 40,000 psi or higher, the water warms up quickly.
In addition, many machine shops are without air conditioning. Combined with other running equipment, air temperatures may be higher than optimal for your machine.
All of this means that if your water supply temperature is over 70° F (21° C) or if you are recirculating your water, it can quickly get too warm. The warmer the water, the more wear will occur on the pump. Water provided to the OMAX pump should be less than 70° F (21° C).
In particular, the pump seal life shortens dramatically with water temperatures above 70° F and faster failures occur at higher temperatures.
If you have a closed loop system or high water supply temperature, you should use a Chiller System to keep the temperature below 70° F to increase the life of your high-pressure pump.